Multistage propeller pump



Dec. 22, 1942. R. R. CURTIS 2,306,301

MULTISTAGE PROPELLER PUMP Filed March 14, 1942 2 Sheets-Sheet 1 Dec. 22, 1942. R. R. CURTIS MULTISTAGE PROPELLER PUMP Filed March 14, 1942 2 Sheets-Sheet 2 Patented Dec. 22, 1942 D STATES PATENT OFFICE MULTISTAGE PROPELLER PUMIP Russell R. Curtis, Dayton, Ohio, assignor to Curtis Pump Company, Dayton, Ohio, a corporation of Application March 14, 1942, Serial No. 434,718

15 Claims.

' the carburetor -of a vehicle to which the fuel system, is applied. The pump includes a bellmouthed shaped shield or guide for directing, to the agitators, the liquid to be treated and pumped. The guide is arranged for directing, in one or more paths, the separated gases and vapors out of the path of the incoming liquid.

The agitators beat out, in bubbleform, the occluded gases and vapors in the liquid and also induce, in the cavities or pockets behind the rotating blades thereof, the formation of gas and vapor from the volatile liquid ingredients. Such an arrangement of elements effects a more efficient separation of gases and vapors from the liquid fuel than has been possible in present known devices.

While the agitators are primarily effective for separating the gases and vapors from the fuel. they also sufliciently discharge the fully liquid fuel under pressure for normal operations. However, should it be necessary to discharge the fuel at greater than normal pressures, then a pumping impeller may also be provided to receive fully liquid fuel from the agitators and pressure the liquid to a delivery line.

It is, therefore, an object of the present invention to provide improved agitating means for booster pumps which are adapted to more efficiently beat out bubbles of gases and vapors from liquids while simultaneously pressuring the bubble-freed liquid.

A further object of this invention is the provision of a multi-stage propeller pumpwherein the propellers successively act on a liquid to beat out bubbles of gases and vapors from the liquid, while simultaneously pressuring the bubble-freed liquid.

Another and further object of this invention is the provision of a propeller pump for consecutively treating liquid material as it flows through a localized passage to free the material of gases and vapors and simultaneously pressure the gas and vapor-freed material.

Another and further object of this invention is the provision of a pump having a guide spaced from the pump for guiding liquid fuel in a path to the pump inlet and a plurality of agitating propellers positioned in the guided liquid fuel for beating out bubbles of gases and vapors therefrom, which bubbles are 'guided away from the fuel in said path.

A further object of this invention is the provision of a pump having a plurality of hollow 'members spaced from each other and from the pump to guid liquid fuel in a path to the pump inlet with agitating propellers adjacent each of said hollow members in the guided path of liquid fuel for simultaneously pressuring and beating out bubbles of gas and vapor from the liquid which bubbles are guided between said hollow members away from said path.

A still further object of this invention is the provision of a'booster pump assembly having a plurality of agitating membersfor simultaneously pressuring liquids and beating out bubbles of gas and vapor therefrom and an impeller for increasing the pressuring of the gas and vaporfreed liquids.

Another object of this invention is to provide a booster pump having a plurality of agitating propellers and a pumping impeller driven from the same source.

A specific object of this invention is to provide a booster pumpassembly adapted for aircraft fuel systems, wherein agitating propellers successively treat a liquid fuel to generate bubbles of gas and vapor, whereinthe bubbles are guided away from the bubble-freed liquid and wherein the bubble freed liquid is pressured by an impeller to the outlet pump.

The novel features believed to becharacteristic of the present invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and manner of construction, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

Figure l is a fragmentary vertical cross-sec tional view, with parts in elevation, of a booster pump and fuel tank assembly in accordance with this invention;

Figure 2 is a plan view of the booster pump asse glilly as seen when disconnected from the fuel ta Figure 3 is a view similar to Figure-1 illustrating a modified form of booster pump in accordancewith this invention;

Figure 4 is a plan view of the booster pump assembly illustrated in Figure 3, when disconnected from the fuel tank; and,

Figure 5 is a' fragmentary vertical cross-sectional view, with parts. in elevation, of another form of booster pump in accordance with this invention.

In Figure 1, the reference numeral Ill designates a fuel tank, vented as at Illa, and contain-- ing a pond P of liquid fuel such as gasoline.. The

, bottom wall of the tank has a circular aperture flange It! for mounting on the bottom wall of the tank II. This flangereceives therethrough cap screws 19 at spaced intervals therearound which are threaded into blind tapped wells in the mounting rin II. The mounting ring may be welded, soldered or otherwise secured to the bot- .thereof to underlie the throat ring 2|.

pumping vanes define, with the throat ring 2| shield 2'! together form a curved guide for the flow of liquid fuel from the interior of the tank l0 axially into the inlet throat opening 23. The co-actingcurved inner surfaces of the annular shields provide acurvature which greatly enhances the pumping capacity of the booster pump since the curvature flares outwardly at the inlet point, it converges at a slower rate.

The booster pump l3 has an impeller assembly 28 mounted on thedrive shaft. II. This impeller assembly includes a disk or flange portion 23 spanning the inlet or aperture'of the throat ring and'communicating freely around the periphery thereof with the inner rim of the pumping or volute chamber l4. Pumping vanes are mounted on the flange 23 around the periphery These and .the flange 29, open ended pumping channels communicating at their outer ends with the pumping or volute chamber I4 and at their inner tom wall of the tank. The casing defines a circular opening 20into which a throat ring '2I is seated and secured to the casing by means of cap screws such as 22.

The throat ring 2| has an aperture 23 therethrough for joining the interior of the tank I II with the pumping or volute chamber ll. The

' aperture is flared outwardly to provide an inlet mouth for the booster pump l2, and, if desired, may also be slightly flared at the bottom thereof to increase the passageway to the pumping or volute chamber H.

A plurality of standards or ribs 24 are spaced around and extend upwardly and inwardly from point intermediate the top and bottom of the shield. The face then converges at a slower rate from this point to the bottom or'discharge end of the shield. The smooth continuous curvature of the inner face is especially designed for a high fluid flow capacity.

Additional standards or ribs 26 extend upwardly from the ribs 24 to carry at their upper ends another bell-mouthed annular shield 21. The ribs 26 carry the shield 21 in spaced relation above the shield 25. p v

The shield 21 has an inner face 210 which, as shown in Figures 1 and 2, converges from the upper end of the shield at a relatively high rate to a point intermediate the top and bottom of the shield in much the same manner as the lower shield 25. Similarly, the face then converges at at slower rate from this point to the bottom or discharge end of the shield. Th smooth continuous curvature of th inner face 21a is also especially designed for a high fluid flow capacity.

It will be noted that'the portion of the inner face 25a ofthe shield 25 which is not overlapped by the shield 21 and the inner face 21a of the ends with the flared inlet of the throat ring.

A can or fairing member 3| extends upwardly from the impeller, disk 23. The outer surface of the fairing member tapers upwardly from the pumping'channels through the throat ring. As best shown in Figure 1, the axial curvature of the fairing member follows substantially the curvature of the throat ring aperture to guide the liquid to the pumping channels. 7

It is preferred that the drive shaft ll extend through the fairing member 3| to receive a fourbladed propeller assembly 32 to be mounted on the free end of the fairing member 3|. The blades of the propeller are spaced above the throat .ring 2| and below the shield 25 where they are in transverse communication with the liquid between the shield and the throat ring.

A tubularspacer 33 is received over the end of the shaft I! to seat on the 'hub of the propeller assembly 32. A second four-bladed propeller assembly 34 is mounted on the spacer 33 and maintained in position thereon by a cap screw 35 which is threaded into a tapped recess (not shown) in the end of the shaft II. The blades of the propeller 34 are spaced above the shield 25 and below the shield 21 where they are in transverse communication with liquid between the shields.

Liquid fuel from the pond P flows through the shields which guides the liquid in a path axially to the inlet aperture 23 of the throat ring. This path of flow of the liquid fuel is illustrated in in Figure 1, and eventually burst at the surface.

of the pond into the atmosphere to liberate the gases or vapors.

It will be noted that the propeller 32 is aligned with a space between the throat ring and the annular guide shield 25, while the propeller 34 isaligned with a space between the guide shields 35 and 21. This relation of the elements permits the bubbles of gases and vapors to be thrown outwardly by the propeller blades in the paths illustrated.

Obviously, the greatest separation of entrained gases and vapors from the liquid into bubble form will occur by the agitation of the upper propeller 34. The lower propeller 32 is an auxiliary propeller whereby further gas and vapor separation may be effected.

It has been found that the placing of propellers in such a tandem relation effects a complete separation of all entrained. gases or vapors from the liquid into bubble form before the liquid flows through the inlet opening of the pump defined by the throat ring. Furthermore, each of the agitating propellers has the blades thereof at an angle or pitch arranged to push the liquid toward the pump inlet 23. Thus, as shown in Figure 2, the blades of both propellers are pitched so that, when they are driven in a clockwise direction, as indicated by the arrows, they will scoop the liquid to trap it thereunder thus giv ng the liquid a downward push. This somewhat pressures the liquid even though it is in transverse communication with the pond to effect a constant flow of liquid into the pump.

The gas and vapor-freed liquid is then acted upon by the pumping vanes 30 of the impeller 28. Thus the pumping vanes 30 act only on fully liquid fuel to further pressure the fuel into the pumping or volute chamber where it is d scharged through the outlet into a delivery l ne leading to the fuel pump of the engine of the vehicle with which such a fuel system is used.

In certain fuel systems installations and under certain conditions, it has been found that the agitating propellers may sufiiciently pressur the liquid to the pump without the need of providing an impeller for this purpose. A pump construction of the type in which the impeller assembly has been eliminated is illustrated in Figure '3.

In the modification shown in Figures 3 and 4, the vented fuel tank I!) has its bottom wall apertured and a mounting ring carried thereon in much the same manner as previously described. A pump 40 has a, casing 4|.defining angularly extending legs 4.2 and 43 which converge into an out-turned annular flange 44. The flange has an upwardly extending pilot portion which seats within the aperture in the bottom of the wall of the tank I0. Cap screw 46, spaced around the annular flange '44, .extend therethrough into threaded engagement within blind tapped openings in the mounting ring thereby securing I the pump to the tank.

The casing 4| has an inwardly tapering surface 41 adjacent the pilot portion 45 and which surface communicates with a pumping channel 48 which sweeps downwardly in a curve through the. leg 43.

A plurality of standards or ribs 49 extend upwardly from the pilot portion 45 of the casing. An annular ring or guide shield 50 is carried by the ribs 49 intermediate their ends and spaced above the pump casing. It will be noted that the guide shield 50 is substantially triangular in cross-section and that a thickened inner portion provides a substantially cylindrical opening.

The upper ends of the ribs 49 have secured thereto a bell-mouthed annular shield 5| which shield is spaced from the shield 50. The shield 5| has an inner face-5|a which, as best shown in Figure 3, converses from the upper end of the shield at a relatively high-rate to a point intermediate the top and bottom of the shield. The face then converges at a slower rate from this point to the bottom or discharge end of the shield. The inner face 5|a has a smooth continuous curvature especially designed for a h gh fluid flow capacity. This particular curva- .52 which is driven by a source of motive power,

I such as an electric motor (not shown).

the like threaded to the free end of the drive,

Spaced four-bladed propeller assemblies 53 and 54 are mounted on the drive shaft 52 with a. spacer 5-5 therebetween and a cap screw 56 or shaft against the propeller 54.

The propeller 53 is arranged in alignment with and spaced between the pump casing and the guide shield in transverse communication with liquid therebetween. The propeller 54 is arranged in alignment with the space between the guide shields 50 and 5| in transverse communication with liquid therebetween.

As the propellers 53 and 54 are rotated in a clockwise direction, as shown by the arrows in Figure 4, the blades of the propellers are pitched as described above to scoop the liquid and push it into the casing 4| by the driving shaft 52, the

"tending arrows.

liquid from the pond P is drawn and pushed downwardly as indicated by the downwardly ex- The liquid fuel flowingthrough the guide shield 5| is also agitated by the propeller 50 to separate any entrained gases or vapors from the liquid in a bubbl form and to generate into bubbles any gases or vapors loosely,

fixed or dissolved in the liquid. These bubbles B are thrown outwardly by the propeller blades through the space between the guide shields where they rise through the pond P in a widening path to eventually burst at the surface of the pond to liberate the gases or vapors. Likewise, the propeller 53 agitates the liquid fuel received from the propeller 54 to further separate any gases or vapors left in the liquid into bubbles, which bubbles are thrown outwardly through the space between the pump casing and the guide shield 50 where they rise in the pond to eventually burst into the surface thereof and liberate the gases or vapors.

The tandem action of the propellers on the liquid flowing through the guide shields is thus the same as that previously described with the device illustrated in Figure 1.

In the pump illustrated in Figure 3, the liquid fuel as it leaves the propellers 53 and 54 is Pressured sufficiently so that fully liquid fuel is eventually discharged through the pumping channel 48 and the outlet 43 and from there into a line leading into the fuel pump of the engine.

Figure 5 illustrates a further modified form, of

pump casing It extends upwardly to the same height as the'guide shield II of Figure 8. The pump casing I has an annular flange 6| by which the pump is secured to a fuel tank in the same manner as illustrated and described previously herein. A central portion 62 of the easing isi'ormed as an extended pilot to be inserted through an opening in the bottom wall of the fuel tank and terminates in an inwardly tapered for the same reasons as the inner face of the shields 21a of Figure 1 and-Ila of Figure 3.

A drive shaft 61 carries thereon spaced fourbladed propellers 68 and 69. These propellers are substantially of the same diameter and inthe same spaced relation as in Figures 3 and 4. The

propeller 68 is mounted entirely within the pumping channel 64 while the propeller 69 is in alignment with the space between the pilot portion 62 of the casing and the guide shield 66. The propeller 69 agitates liquid fuel flowing through the guide shield 66 for separating from the fuel any gas and vapors entrained therein. The separated gas and vapor forms into bubbles which are thrown outwardly through the space between the pump casing and the guide shield 68. The gas and vapor-freed liquid fuel is then pressured by the propeller 69 to the casing inlet and to the propeller 08. As the propeller it lies wholly within the pumping channel 64, the fully liquid fuel will be additionally pressured to the discharge of the pump.

It will be apparent from the foregoing that a multi-stage propeller pump is provided herein by which liquid fuel flowing through a guided path is acted on successively by th propellers to beat out bubbles of gas and vapor entrained therein. The fully liquid fuel is pressured by the propellers simultaneously with the agitating or beating action. Should the pressure of the 7 While particular embodiments of this invention have been illustrated it will, of course, be understood that the invention should not be limited thereto, since many other modifications may b made and, therefore, it is contemplated by the appended claims to cover all such modifications 5 as fall within the true spirit and scope of the present invention.

I claim as my invention:

l. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a pump having an inlet for receiving liquid material from .said source, an outlet for discharging fully liquid material, tandem propeller means between said inlet and said outlet for successively agitating the liquid material received through the inlet from said source to beat out bubbles of gas and vapor therefrom and for pressuring the gas and vapor freed liquid material toward said pump outlet, and means deflninga path separate from the inlet for bubble flow from at least one of said propeller means back to said source. 4

2. A device adapted for discharging fully liquid material, .such as volatile fuel, from a source of 1 liquid material which comprises'a pump having an inlet for receiving liquid material from said source, an outlet for discharging fully liquid ma-' terial, and tandem propeller means adjacent said pump inlet positioned to act in the liquid material flowing from the source to the pump outlet, at least one of said propeller means being arranged for transverse communication with a body of liquid material surrounding the liquid material entering the inlet, said propeller means successively agitating the liquid material before it becomes trapped in the pump to beat out bubbles of gas and vapor therefrom and-for pressuring 'the gas and vapor freed liquid material toward said pump outlet.

3. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a pump having an inlet for receiving liquid material from said source, an outlet for discharging fully liquid material, means arranged in tandem positioned in advance of the pump inlet to act in the liquid material flowing to the pump inlet for agitating and pressuring said liquid material toward the pumpinlet, said means including a plurality of propeller means successively agitating the liquid material to beat out bubbles of gas and vapor therefrom, and means defining paths extending outwardly from the propeller means back to the source.

4. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a casing having an inlet and an outlet, a guide shield mounted in advance of and spaced from said casing inlet, and means arranged in tandem and positioned to act in the liquid material flowing through a path defined by the shield and the casing for agitating and pressuring said liquid material, said means including a plurality of propeller means successively agitating the liquid material to beat out bubbles of gas and vapor therefrom.

5. A device adapted for discharging fully liquid material, suchv as volatile fuel, from a source of liquid material which comprises a casing having an inlet and an outlet, guide shield means mounted, in advance'of and spaced from said casing inlet, and means arranged in tandem and positioned to act in the liquid material flowing through said guide shield means and said casing for agitating and pressuring said liquid material, said tandem arranged means including a plurality of propeller means successively agitating the liquid material to beat out bubbles of gas and vapor therefrom, at least one of said propeller means being arranged for transverse communication with a body of liquid material surrounding the liquid material flowing through said guide shield.

6. A device adapted for discharging fully 'liquid material, such as volatile fuel, from a source of liquid material which comprises a casing defining an inlet and an outlet, a plurality of spaced guide shields mounted in advance of and spaced from said casing inlet, and a plurality of propellers positioned in the flow path defined by the shields and arranged in tandem for successively agitating and pressuring liquid material flowing through said guide shields to beat out bubbles of gasand vapor from the material. said propellers being arranged for transverse communication at the spaces between said shields and casing with a body of liquid material surrounding the liquid material flowing through said shields.

7. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a casing defining an inlet and an outlet, a plurality of spaced guide shields mounted in advance of and spaced from said casing inlet, apropeller in alignment with each space between adjacent guide shields and between a guide shield and the casing, said propellers being arranged in tandem in the flow path defined by the shields and means for corotating said propellers for successively agitating and pressuring liquid material flowing through said guide shields to beat out bubbles of gas and vapor from the material.

8. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a casing de-- fining an inlet and an outlet, a plurality of spaced uide shields mounted in advance of and spaced from said casing inlet, said guide shields defining a curved localized flow path to the casing inlet, a propeller in alignment with each space adjacent said guide shield, and means mounting said propellers in tandem in the flow path and co-rotating the propellers for successively pressuring and agitating liquid material flowing in said curved path to beat out bubbles of gas and vapor and to throw said bubbles outward-- ly through said spaces in alignment with the propellers.

9. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a casing defining an inlet and an outlet, a plurality of ribs around said casing-inlet and extending away from the casing, a pluralityof guide shields carried by said ribs in spaced relation to each other and to said casing, said guide shields defining a curved localized flow path for increasing theflow of liquid material from the source to said casing inlet, propellers within said guide shields aligned with the spaces adjacent said guide shields, and means for rotating the propellers for successively axially pressuring and radially agitating the liquid material flowing in said curved path to beat out bubbles of gas and vapor and to throw said bubbles outwardly through the spaces in alignment with the propellers.

10. A booster pump construction comprising a casing defining an annular pumping chamber, an impeller mounted centrally of said pumping chamber and extending into the periphery thereof, a throat ring having an aperture therethrough flaring away from said pumping chamber, spaced uide shields in advance of and spaced from said throat ring defining a flow path to the throat ring aperture, an agitating propeller in said flow path between said throat ring and'an adjacent guide shield, another agitating propeller in said flow path between said spaced guide shields, said propellers being arranged for' free transverse communication through the spaces adjacent thereto with a body of'liquid surrounding the guide shields, and means for rotating said impeller and propellers for successively pressuring said liquid material toward said pumping chamber and -i'or successively beating out bubbles of gas and vapor from the liquid and throwing the bubbles outwardly through said adjacent spaces.

11. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a casing defining an inlet and an outlet, overlapped spaced annular guide shields mounted in advance of and spaced from said casing inlet, said guide shields co-acting to define afiared flow path converging toward said casing, and

12. A device adapted for I discharging fully' liquid material, such as volatile fuel, from a source of liquid material which comprises 9, casing defining an outlet and an inlet having a flared mouth, guide shield means mounted in advance of and spaced from said casing inlet defining a flow path to said inlet, and a plurality of propellers positioned to act on liquid flowing through the guide shield and casing for pressuring and beating out bubbles of gas and vapor from the liquid material.

13. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a casing defining an inlet and an outlet with a channel therebetween, a guide shield mounted in advance of and spaced from said casing inlet to define a flow path to said inlet, and a plurality of propellers positioned to act on liquid flowing through said shield and said casing chan-.

nel for beating out bubbles of gas and vapor from the liquid material and for pressuring the beaten liquid material toward the casing outlet.

14. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a casing having a channel therethrough defining an inletat one end and an outlet at the other end, a relatively shallow annular guide shield adapted to be mounted in the source of liquid material in spaced relation from said casing at the inlet end thereof, a propeller positioned in the flow path through the shield in alignment with. the space between said shield and casing, an additional propeller in said channel, and means for rotating said propellers for successively pressuring and beating out bubbles of gas vapor from the liquid material.

15. A device adapted for discharging fully liquid material, such as volatile fuel, from a source of liquid material which comprises a casing having a channel therethrough defining an inlet at one end and an outlet at the other end, a. relatively shallow annular guide shield adapted to be mounted in the source of liquid material in spaced-relation from said casing at the inlet end thereof, said shield having a curved inner surface and a relatively fiat outer surface. the

adjacent surfaces of said shield and casing'slopthrougfisaid shield into and through said channel. I

. RUSSELL, R. CURTIS. 

